A plotting Instrument for sundials on irregular surfaces - PowerPoint PPT Presentation

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A plotting Instrument for sundials on irregular surfaces

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Possibility of lay out big sundials highly positioned ... 12 intervals match to a graduated sector of 23 Precision of 5 minutes of arc. 5 ... – PowerPoint PPT presentation

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Title: A plotting Instrument for sundials on irregular surfaces


1
A plotting Instrument for sundials on irregular
surfaces
  • Gérard Labrosse

2
Introduction
  • Methodical put in function
  • Indispensable presence of the sun

3
Advantages
  • Two perpendiculary lasers
  • Possibility of lay out big sundials highly
    positioned
  • Not necessary to know the declination of the wall

4
Latitude settings
  • 12 intervals match to a graduated sector of 23
  • Precision of 5 minutes of arc

5
Billsticking of the hour angle H
  • Ball pushed by a coin (7,5)
  • Any other hour angle

6
Billsticking of the declination
  • Solstices and equinoxes positioned with 3 holes
    an axis with symbol d
  • For any declination of the sunthe disc can be
    blocked with a small plastic stopper which is
    pusched with a screw (with a sun decoration)

7
Horizontality adjustment
  • An aluminium tray with 15,75" on each side  
  • 3 screws for adjustment
  • Double precise spirit level

8
Alignment on the local meridian
  • A compass for a first rough alignment
  • A viewfinder with a lens and a target

9
Drawing the hour lines
  • Adjust the position of the lower disc on the
    value of the hour angle (15 for 13h)
  • Pivot the upper disc from the top to the bottom

10
Drawing the diurn curves
  • Adjust the value of the sun declination value of
    the hour angle
  • You just have to pivot the upper part from left
    to right

11
Style installation
  • The style is positioned in a way that the laser
    point is visible on its end

12
Œuvres du Père Pardies
13
With a lamp
14
A plotting Instrument for sundials on irregular
surfaces
  • Gérard Labrosse
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